This invention relates to a cutter bit assembly, and in particular to a cutter bit assembly for a mineral winning machine such as a coal plough.
A known coal plough cutter bit assembly has a holder defining a pocket in which a body portion of a cutter bit is received. The cutter bit may have a projection which hooks into a recess in an end wall of the holder, while the other end of the cutter bit body is held in place by a detachable securing device. The detachable securing device may be a liner which is inserted into a gap between opposed surfaces of the cutter bit body and the holder. A known type of liner is constituted by a thin metal plate which is loosely inserted into this gap. The plate (liner) is held in place by, for example, a dowel sleeve which is driven through aligned bores in the liner and the cutter bit body. In order to release the cutter bit from the holder, it is first necessary to release the dowel sleeve and to remove the liner. The cutter bit can then be moved forward in the pocket a sufficient distance to unhook the projection of the cutter bit body from the recess in the end wall of the holder. Thereafter, the cutter bit can be swung laterally out of the pocket of the holder, the open end of which pocket is directed towards the face being won. An assembly of this type is described in DE-PS No. 1291708.
In another known cutter bit assembly of this type, the dowel sleeve is replaced by a locking plate. The locking plate is bent over towards the outer face of the holder (or the cutter bit body) to hold the liner in place. (See DE-OS No. 2 355 554).
In the known types of cutter bit assembly, the parts of the holder which support the cutter bit body undergo deformation and wear during use. This is because of the jolting of the cutter bit body against the support faces of the holder. The wear of the support surfaces of the holder (and the wear of the associated parts of the cutter bit body) is undesirable, as it results in a loose fit of the cutter but within the holder.
The aim of the invention is to provide a cutter bit assembly whose cutter bit can be firmly and reliably secured in its holder; and which can, when necessary, be quickly and easily retightened.